1. Technical Field
The present invention generally relates to processing systems and methods for food, and more particularly, to a food surface microbial intervention system and method that provide a 5-log (i.e., 100,000 times) reduction in the amount of microbial pathogens on the surface of food products.
2. History of Related Art
Fruits, vegetables, and other foods are allowed to remain in contact with soil, insects, and animals during the time of their growth and harvest. Thus, fresh produce, for example, maintains populations of 10.sup.4 and 10.sup.5 microorganisms/gram when they arrive at the packing house. Such microorganisms include coliform bacteria, including Enterobacter; Klegsiella spp., and Escherichia coli. The bacteria population tends to remain relatively stable, with no significant influence exerted by temperature, total precipitation, or length of the day during harvest. Such bacteria may become natural contaminants of frozen concentrated fruit juices.
Since improperly handled food products can serve as a vehicle for the transmission of microorganisms to humans, the elimination of such surface bacteria and pathogenic microbes (which include spoilage organisms) has a tremendous value to the food and health industries. For example, there is currently a requirement by the Food and Drug Administration and the United States Department of Agriculture that all juice products include the following warning statement on package labels after Nov. 5, 1999.
WARNING: This product has not been pasteurized and, therefore, may contain harmful bacteria that can cause serious illness in children, the elderly, and persons with weakened immune systems.
Thus, there are not only safety hazards afforded by the presence of these surface contaminants, but also marketing and legal implications.
Several approaches to reducing the number of bacteria on the surface of produce and other foods have been attempted. Common chemical sanitizers, such as chlorine treatments, may be reasonably effective for equipment sanitation, but these chemicals apparently have little effect on microorganisms. Another approach includes steaming herbs, spices, and root/tuber vegetables under pressure, or in a vacuum. Chemical gases may be used to create an antiseptic environment. Each of these processes tends to be expensive and unreliable, fraught with an abundance of complicated equipment which tends to break down, and produce unpredictable results.
Even when simple steam is applied to provide microbial intervention at the surface of food products, it is often the case that expensive and complicated steam generation apparatus is used. Further, the methods of steam production often involve holding times that are overly long; such immersion in steam or hot water tends to adversely affect the organoleptic properties of the food products so treated.
Therefore, what is needed, is an apparatus and method for microbial intervention and pasteurization of food product surfaces which is inexpensive and mechanically simple. Further, the apparatus and method should produce repeatable, reliable results. More specifically, the holding time for the food products to be surface pasteurized should be consistently maintained at the minimum level necessary to accomplish a 5-log reduction in the amount of surface bacteria and/or microorganisms present on external surfaces of the food. A minimum number of steps to implement the process of such a method should be required, and preferably, no special chemicals should be introduced into the microbial intervention process.